Surface electrode adapted for use with rheographic apparatus

ABSTRACT

A quickly attachable and detachable surface electrode arrangement, especially adapted for connecting rheographic apparatus to the extremity of a subject such as a human subject for making impedance measurements. A broad, flexible conductive band is provided, adapted to loop around an extremity of the subject in conductive contact with the skin. A clamp is provided to firmly secure the conductive band in the loop, with the band in good conductive contact with the skin. The clamp is adapted to be connected to a conductor for providing an excitation signal to the subject from suitable rheographic apparatus or other electrical equipment. The electrode and clamp arrangement is also capable of use as a receiver electrode. The clamp is easily attachable and removable since it comprises two outer tangs joined at one end to a base to form a fork, and otherwise includes an elongate center tang or tongue which is also joined to the base of the fork by a flexible, spring portion. The tongue can be depressed through the fork by pinching action of an operator and, when released, will spring back through the fork to firmly engage and clamp a portion of the band placed therebetween. The extended ends of the fork tangs and the tongue are formed of flat conductive material whereby excellent electrical contact is achieved with the conductive band, when it is clamped.

United States Patent [191 Deering et al.

[ Aug. 27, 1974 SURFACE ELECTRODE ADAPTED FOR USE WITH RHEOGRAPHICAPPARATUS [73] Assignee: Beckman Instruments, Inc.,

Fullerton, Calif.

[22] Filed: Jan. 29, 1973 [21] Appl. No.: 327,473

[52] US. Cl. 128/2.l E, l28/DIG. 4, 128/418, 128/416, 339/261, 128/411[51] llnt. Cl. A6lb 5/04, A61n 1/04 [58] Field of Search l28/2.1 E, 2.06E, DIG. 4, 128/416-418, 410-411, 404, 379, 380,

384389, 172.1, 1 C, 303.13; 174/5 SB;

OTHER PUBLICATIONS General Electric Diathermy Electrodes andAccessories, GE XRay Corp., 1934, pp. 14, 25, 28. Electronics and theAged, Radio Electronics, Vol. 36, No. 6, June 1965, p. 29.

Primary Examiner Richard A. Gaudet Assistant ExaminerLee S. CohenAttorney, Agent, or Firm-R. J. S'teinmeyer; J. M. Thomson [57] ABSTRACTA quickly attachable and detachable surface electrode arrangement,especially adapted for connecting rheographic apparatus to the extremityof a subject such as a human subject for making impedance measurements.A broad, flexible conductive band is provided, adapted to loop around anextremity of the subject in conductive contact with the skin. A clamp isprovided to firmly secure the conductive band in the loop, with the bandin good conductive contact with the skin. The clamp is adapted to beconnected to a conductor for providing an excitation signal to thesubject from suitable rheographic apparatus or other electricalequipment. The electrode and clamp arrangement is also capable of use asa receiver electrode. The clamp is easily attachable and removable sinceit comprises two outer tangs joined at one end] to a base to form afork, and otherwise includes an elongate center tang or tongue which isalso joined to the base of the fork by a flexible, spring portion. Thetongue can be depressed through the fork by pinching action of anoperator and, when released, will spring back through the fork to firmlyengage and clamp a portion of the band placed therebetween. The extendedends of the fork tangs and the tongue are formed of flat conductivematerial whereby excellent electrical contact is achieved with theconductive band, when it is clamped.

1 Claim, 5 Drawing Figures PATENIEDAUBZ TIBH 3,831 ,589

1. SURFACE ELECTRODE ADAPTED FOR USE WITH RI-IEOGRAPHIC APPARATUSBACKGROUND OF THE INVENTION The present invention relates to a quicklyattachable and detachable surface electrode arrangement. Moreparticularly, the invention concerns a band and clamp arrangementespecially adapted for use as an excitation electrode or a receiverelectrode for excitation signals to be applied to the extremities of asubject, such as from an associated rheographic apparatus.

Various rheographic systems are utilized in medicine in which anexcitation signal of relatively high frequency is applied to a subject,and a resulting signal is sensed from the subject as an indication ofthe impedance or some other parameter of the subject. In most such casesthe excitation signal is applied to the skin of the subject usually atone or more extremities thereof. Also, in the usual case the resultantsignal from the pa tient is picked up by skin electrodes again attachedto the extremities of the subject.

Various types of skin electrodes have been utilized for this purpose.Perhaps the most common type are flat discs or cups which are secured tothe extremities by straps. These electrodes usually require the use of aconductive jelly to facilitate suitable electrical contact with the skinof the subjects. They may also require the use of straps which aretightly placed upon the extremities of the subject to further facilitatethe electrical contact required. Aside from the discomfort to the patient associated with the use of such electrodes, they are cumbersome touse and time consuming since they require special placement and operatorattention.

Other electrodes such as subcutaneously placed needles could beutilized, if desired, but obviously would result in more patientdiscomfort. Consequently a need has developed in conjunction withrheographic apparatus for a quickly attachable and detachable surfaceelectrode that can be employed as an excitation electrode or as areceiver electrode.

SUMMARY OF THE INVENTION Accordingly, it is an object of the inventionto provide a surface for skin electrode arrangement which overcomes thedisadvantages of skin electrodes mentioned above.

It is another object of the invention to provide a quickly attachableand releasable clamp.

It is a further object of the invention to provide a quickly attachableand detachable band and clamp arrangement which can be easily andquickly applied to the extremities of a subject by even an inexperiencedoperator, in a manner which will provide suitable conductive contactbetween the subject and an electrical instrument such as a rheographicapparatus.

It is yet another object of the invention to provide such a surfaceelectrode arrangement which is extremely easy to manufacture andassemble whereby the electrode is economical to use.

It is yet a further object of the invention to provide a band and clamparrangement wherein the clamp includes two fixed elements and a movableelement adapted to pass therebetween whereby a section of a looped bandclamped therebetween will be placed under tension.

These and other objects of the invention are attained with an electrodeand clamp arrangement which utilizes a wide, flat flexible conductiveband adapted to surround an extremity of the subject and form a skincontacting loop. The arrangement otherwise includes a clamp adapted toslip over the common portion of the looped band for securing the loop.around the extremity with suitable tension to provide good electricalcontact between the loop and the subject. The clamp is adapted to beconnected to a conductor associated with suitable rheographic apparatus.Preferably, the clamp is fabricated such that one or more flat membersare placed in clamping relationship with the band whereby goodconductive contact is established between the clamp and the band. Theclamp is designed such that it can be manufactured from a single stripof conductive material. Consequently the band and clamp are especiallyeconomical to manufacture and use.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing and other objects andadvantages of the invention will become apparent from the followingdetailed description of the invention taken in conjunction with theaccompanying drawings wherein:

FIG. 1 is a diagrammatic view of one preferred embodiment of theinvention associated with an extremity of a subject illustrated indotted outline;

FIG. 2 is an enlarged perspective view of one preferred embodiment of aclamp associated with a portion of a flexible conductive band;

FIG. 3 is a top plan view of the clamp embodiment illustrated in FIG. 2;

FIG 4 is a side view of the clamp arrangement illustrated in FIGS. 2 and3; and

FIG. 5 is a perspective view of an alternative embodiment of a clampsuitable for use with the conductive band illustrated in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION Referring now to the drawings onepreferred embodiment of the invention is illustrated including a band 10adapted to form a loop about an extremity ll of a subject, such as thatillustrated in dotted outline in FIG. 1. Band 10 preferably comprises awide flexible solid strip of conductive material such as aluminum oraluminum foil. However, a band of woven conductive wire or a flexiblecable could be utilized, if desired. Band 10 is sufficiently long toform a loop about the extremity to which the electrode is to be secured,with sufficient material overlapping to provide a common clamping areaas indicated by numeral 15. With the band associated with the extremityand suitably clamped in position, the band exerts relatively lightpressure upon the skin of the subject and provides good electricalcontact there with without the use of conductive cream, although suchcould be utilized with the band if desired.

Band 10 is adapted to be secured to the extremity, as shown, by a clamp12 secured in clamping area 15. In the preferred embodiment, clamp 12 isfabricated of a conductive material and is disposed in good conductiverelationship with band 10. Clamp 12 generally comprises a body portionformed of a single elongate strip of conductive material and anelectrode receptor 17 secured to the body, in a manner describedhereinafter, to receive an electrical conductor, not illustrated. Sincethe clamp is adapted for use in medical applications it should befabricated of a material which is noncorrosible and can be sterilized.

As shown, the body of the clamp includes a fork 18 comprising elongateextended tangs 19, 20 joined at one end to a base 21. Base 21 is formedwith an angular bend therein along a line 22 extending transversely ofthe length of tangs 19, 20, whereby a major portion of base 21 isangularly offset with respect to the tangs at an angle of about 130. Thebody is otherwise bent at about a 90 angle along a line 24, and at abouta 90 angle along a line 25 whereby a connector platform 26 is providedbetween base 21 and a clip portion 28.

Clip portion 28 includes a wide segment 29 of the clamp body adjacentplatform 26, and a tongue 30 of reduced width extending outwardlytherefrom. As shown, a bend is formed in clip portion 28 along a line 32extending transversely of the length of tongue 30. Furthermore, tongue30 is of sufficient length that it extends somewhat beyond the ends oftangs 19, 21. The combined effect of the bends formed adjacent platform26 and the bend along line 32 are such that the extended end of tongue30 is offset upwardly with respect to the tangs by approximately a langle as shown in FIG. 4. Furthermore, the end of tongue 30 is ofsufficiently reduced width that clearance is provided between the sideof tongue 30 and the inner edges of tangs 19, whereby tongue 30 can passback and forth through the fork formed by the tangs when the clamp ispinched and released by an operator. To facilitate this movement, thebody of clamp 12 is preferably formed of flexible spring material suchas tempered steel, or a tempered alloy of conductive material.

An opening preferably of circular configuration is formed in the centerof platform 26. A connector 17 is secured within the opening by suitablemeans. In the embodiment illustrated, connector 17 comprises a femaletype connector having a reduced cylindrical portion on one end adaptedto fit within the opening in the platform. An end 38 of the cylindricalportion is swaged to secure the connector to body 16. Other suitablemeans of securing the connector to the body, such as soldering, could beutilized if desired. Likewise, other types of connectors could beutilized in connection with the clamp without departing from the scopeof the invention. It should also be noted that the tangs and tongue ofthe clamp are fabricated from thin stock and are formed with relativelywide dimensions. Accordingly the contact between the tongue and tangs ofthe clamp and the clamping area of band 10, when the clamp is located ina clamping position, is of sufficient area to ensure good electricalcontact between the clamp and bands.

In use of the clamp and band assembly described herein, the band isplaced around the extremities of a subject by an operator and drawn to alooped position. The clamp is then deformed by pinching action such thatthe tongue is oriented between the tangs and these members are located,respectively, on opposite sides of the common portion of the loop. Theclamp is then released and, due to the spring action of the material itis fabricated of, as well as the offset in the tangs and the tongue, thetongue moves or springs back through the tangs and firmly clamps theband without pinching the skin of the subject or uprooting hair. Theconnector 17 can be connected with a suitable electrode either before orafter the clamping action is accomplished.

Since the normal position of the tongue of the clamp is slightly awayfrom the tangs, the tongue exerts significant force upon the band whenclamped therein. Consequently, the loop formed by the band iseffectively shortened and the band is placed under slight tension aroundthe subject. This enhances the desired electrical contact and tends tohold both the band and the clamp in place.

An alternative embodiment of the invention is illustrated in FIG. 5wherein like elements are identified by like primed numerals. In thisembodiment, the tongue and tangs are reversed. Also this embodiment ofthe invention utilizes a body 45 formed with a curved outline to providesuitable offset between the tongue and tangs. It should be apparent thatthe function of the clamp illustrated in FIG. 5 is similar but reversedto that illustrated in FIGS. 1 to 4.

The clamp and band arrangement described herein comprises a surfaceelectrode which is extremely easy to utilize in that an operator canquickly apply or remove the band from the extremity of the subject.Furthermore, the arrangement provides excellent conductive contact withthe skin of the subject without the use of conductive creams and withoutnoticeable subject discomfort. Electrical contact is greatly facilitatedby the use of a wide conductive band, as well as by the use of tongueand tang members which are flat, and sufficiently wide to contact asignifcant area of the band. Since the tongue over-extends the tangs,the clamp can be easily guided into the clamping position by an operatorwithout injuring the subject. Furthermore the clamp is susceptible ofsterilization and is especially adapted to place tightening force on thelooped band, when clamped therein.

It should be apparent that, if desired, the clamp described herein couldbe used for clamping other objects. Thus, the clamp has utility forpurposes of clamping nonconductive members, and in that event could befabricated of nonconductive material, or without connector 17.

What is claimed is:

l. A surface electrode especially adapted for use as an excitationelectrode for applying electrical signals from an electrical apparatusto an extremity of a subject, comprising a broad flexible conductiveband of sufficient length to form a loop around the extremity of asubject, the ends of the band overextending each other forming a commonclamping area adapted to be adjacent to the extremity,

clamping means formed of a conductive material and adapted to beassociated with an electrical apparatus for engaging said band at saidclamping area to confine and tighten the looped band in firm conductiveengagement with said extremity, said clamping means including a bodyformed of a thin strip of resilient material, said body having a forkformed at one end thereof by two extending, straight, spaced-aparttangs,

said body having a tongue formed at the other end thereof having a widthless than the gap between said spaced-apart tangs,

said body being formed in a doubled shape so that the tangs and thetongue extend in generally the same direction, with the tongue centeredbetween the tangs and parallel thereto, said tongue and said tangs beingflat, the end of the tongue being pressed through the gap between thetangs and firmly engaging said conductive band at said clamping areawith the tangs and tongue being positioned on opposite sides of theclamping area for engaging the extremity in a tight relationship.

1. A surface electrode especially adapted for use as an excitationelectrode for applying electrical signals from an electrical apparatusto an extremity of a subject, comprising a broad flexible conductiveband of sufficient length to form a loop around the extremity of asubject, the ends of the band overextending each other forming a commonclamping area adapted to be adjacent to the extremity, clamping meansformed of a conductive material and adapted to be associated with anelectrical apparatus for engaging said band at said clamping area toconfine and tighten the looped band in firm conductive engagement withsaid extremity, said clamping means including a body formed of a thinstrip of resilient material, said body having a fork formed at one endthereof by two extending, straight, spaced-apart tangs, said body havinga tongue formed at the other end thereof having a width less than thegap between said spaced-apart tangs, said body being formed in a doubledshape so that the tangs and the tongue extend in generally the samedirection, with the tongue centered between the tangs and parallelthereto, said tongue and said tangs being flat, the end of the tonguebeing pressed through the gap between the tangs and firmly engaging saidconductive band at said clamping area with the tangs and tongue beingpositioned on opposite sides of the clamping area for engaging theextremity in a tight relationship.